Process of color photographic printing paper

ABSTRACT

A STABILIZATION COMPOSITION FOR USE IN PROCESSING PHOTOGRAPHIC PRINTING PAPERS, COMPRISING A WATER-SOLUBLE ALUMINUM SALT, A POLYCARBOXYLIC ACID OR A SALT THEREOF, AND BENZOIC ACID OR A SALT THEREOF, IS DISCLOSED.

United States Patent U.S. Cl. 96-56 12 Claims ABSTRACT OF THE DISCLOSURE A stabilization composition for use in processing photographic printing papers, comprising a water-soluble alumi num salt, a polycarboxylic acid or a salt thereof, and benzoic acid or a salt thereof, is disclosed.

BACKGROUND OF THE INVENTION The present invention relates to a stabilizing bath for color photographic printing papers and more particularly to a stabilizing bath or composition for color photographic printing papers for improving the physical properties of the color photographic papers processed, resulting in excellent and stable images on said printing papers, which can be stored for long periods of time, and also having excellent stability thereof.

Color photographic printing papers processed by the stabilizing bath of the present invention have the following excellent characteristics:

(1) When the color prints are stored in an album or under various conditions for long periods of time, they show neither a tendency to stick nor to adhere.

(2) 0n ferrotype drying, they show no adhesion to the ferrotype plate and also no static is formed.

(3) The pre-heating operation of ferrotype drying is unnecessary.

(4) The color print thus processed is very stable to light.

(5) When color photographic printing papers stored for a long period of time without being exposed are processed, excellent and stable color photographic images are obtained.

Moreover, the stabilizing bath of the present invention has the following desirable properties:

(1) No mold is generated in the stabilizing bath.

(2) The stabilizing bath has a high buffer function.

Ordinary processing for photographic printing paper includes a drying step, for example, by means of a ferrotype dryer. In particular, in the case of subjecting processed color photographic printing papers to ferrotype drying, the hardening bath and the stabilizing bath in the photographic processing give rise to.various difliculties since the color photographic light-sensitive printing papers to be subjected to the ferrotype drying have been processed by a number of processing steps. For example, when a color photographic printing paper is processed by the process as described in The British Journal of Photog raphy; Sept. 27; 838-840 (1968) and the specification of British Pat. No. 736,881 and the printing paper then is subjected to high temperatures and high speed ferrotype drying, the printing paper sticks to the ferrotype plate. To overcome such difliculty, in the case of processing a color photographic printing roll paper, a pre-dryer and a rewetting means are employed as described in Kodak Products for the Professional 77 (1968/ 69). However, such improvement is accompanied by the drawback of employing additional steps. Also, other attempts such as im- Patented May 30, 1972 "ice provements in cleaning the ferrotype plate or improvements in various chemicals for cleaning the ferrotype plate have been provided but such attempts are considerably troublesome to use.

On the other hand, by processing a color photographic printing paper, which has been subjected to color development, stop-fixing, washing, bleaching, washing, hardenerfixing, and washing, in the stabilizing bath of the present invention, the printing paper thus processed can be directly subjected to high temperature, high speed ferrotype drying without the necessity of a pre-drying step. Furthermore, when the stabilizing bath of the present invention is employed, the drying speed in the ferrotype drying step is faster than the time required for ferrotypedrying a printing paper which has been subjected to conventional photographic processing and a pre-heating procedure. In addition, the printing paper subjected to ferrotype drying after being processed in the stabilizing bath of the present invention is very excellent as compared to a printing paper subjected to ferrotype drying after being processed in conventional processings and pre-heating. Also, when a color photographic printing paper subjected to the aforesaid conventional photographic processings is subjected directly to a low speed ferrotype drying, the paper is charged statically, whereas a printing paper processed using the stabilizing bath of the present invention is charged statically only minimally.

Another feature of a color photographic printing paper processed using the stabilizing bath of the present invention is that the physical properties of the printing paper are excellent when the paper is stored under various conditions. Processed printing papers are usually stored in a condition in which the printing papers are adhered to theboard of an album or attached to a transparent film cover of the page of an album, or stored in bags or cases. On the other hand, the temperature and humidity for storing printing papers varied according to the season and place of storage. In general, on storage, the occurrence of difliculties such as adhesion or sticking of the printing papers is minimized under conditions of low temperature and low humidity, but the manner of storage is considerably restricted in high humidity conditions. For example, when a color photographic printing paper processed according to the process described in the abovementioned British Journal of Photography and the specification of the aforesaid British patent are stored under high humidity conditions, the following undesirable difliculties tend to occur.

(1) When the printing papers thus processed are afiixed to the both sides of the pages of a usual album, the printing papers stick to each other at the superposed parts.

(2) When the printing papers are allixed to transparent covers of the pages of an album, Newton rings are formed or the surfaces of the printing papers are contaminated.

(3) When the printing papers are stored in bag or case in a superposed state, the printing papers stick to each other.

(4) In any case, the printing papers become sticky and the printed images are degraded by fingerprints, dust, and the like.

On the other hand, employing the stabilizing bath of the present invention, the above-mentioned difiiculties can be overcome.

Further, as is well known, the stabilizing bath used in the processing of photographic light-sensitive elements has an important relation to the stability of the image and various studies have been made about it. For example, the process disclosed in U.S. Pat. No. 2,788,274 may be effective in the prevention of fading of color images, but

. it is less eifective in preventing the formation of stains due to light and heat. Thus, preventing the occurrences of both of these difliculties is proposed in The British Journal of Photography at 588-589 (July 8, 1966) and at 838-840 (Sept. 27, 1968). However, when a color photographic printing paper is processed in the stabilizing bath of the present invention, the printing paper thus processed is excellent under a high humidity condition as compared with processing a photographic printing paper in the stabilizing bath as described in the above-mentioned The British Journal of Photography and has an image stability almost the same as that of the latter case under other conditions.

Conversely, it is known that molds are formed in photographic light-sensitive elements or processing baths and to prevent the generation of molds, various attempts have been proposed. For instance, some approaches are disclosed in Photographic Science and Engineering; 3, 132 (1959) and in the specification of US. Pat. 3,093,479. However, the stabilizing bath of the present invention is concerned less with the generation of molds and, also, the photographic light-sensitive elements processed in the stabilizing bath of the present invention exhibit good mold prevention.

DESCRIPTION OF THE INVENTION The inventors have found that by incorporating a watersoluble aluminum salt in an aqueous solution containing a bufier, the physical properties of color photographic printing papers processed in the solution can be improved markedly. Also, it has been found that by further adding benzoic acid or a salt thereof to the aqueous solution, generation of molds can be prevented.

Thus, the stabilizing bath of the present invention is an aqueous solution containing a water-soluble aluminum salt, a polycarboxylic acid or a salt thereof, and benzoic acid or a salt thereof.

DETAILED DESCRIPTION OF THE INVENTION Examples of the water-soluble aluminum salt used in the present invention are double salts such as potassium alum or ammonium alum and metal salts such as aluminum sulfate. Examples of carboxylic acids are citric acid, oxalic acid, malonic acid, maleic acid, tartaric acid, succinic acid, glutaric acid, adipic acid, lactic acid, crotonic acid, aconic acid, diglycocholic acid, itaconic acid, and citraconic acid. As the salt of the polycarboxylic acid, there are the alkali metal salts and the ammonium salts thereof. The polycarboxylic acid or the salt thereof acts as a buffer in the stabilizing bath of the present invention.

Moreover, as the salt of benzoic acid, there are illustrated the alkali metal salts and the ammonium salts thereof.

The preferred proportions of the above-mentioned compounds in the stabilizing bath of the present invention are shown in the following table.

Optimum Amount amount Compound (g-fL) (E-IU Water-soluble aluminum salt 15-40 20-35 Polycarboxyllc acid or salt thereof 2-10 3-7 Beuzoie acid or salt thereof 0. 1-10 0. 2-1

Moreover, by adding boric acid or an alkali metal salt thereof to the stabilizing bath of the present invention, the buffer ability of the stabilizing bath can be further increased. In such case, the amount of the additive is usually from 2 to 10 g./l., preferably from 4 to 6 g./l.

The stabilizing bath of the present invention can be employed with any of the usual color photographic printing papers but more effectively, it is used with the color photographic printing papers having on a support, such as a baryta-coated paper or a resin-coated paper, the lightsensitive layers containing an acetanilide yellow coupler as described in the specification of British Pat. No. 1,113,- 038, a pyrazolone magenta coupler as described in the specification of British Pat. No. 1,142,553, and a phenolic cyan coupler as described in the specification of US. Pat. No. 2,801,171.

Also, since the stabilizing bath of the present invention has a sufliciently high buifer activity, any type of processing method, such as tank processing, tray processing, and drum processing, can be employed. In particular, the stabilizing bath of the invention is suitable for the continuous processing of a large quantity of color photographic printing papers.

The merits of using the stabilizing bath of the present invention, such as the improvement of physical properties of color photographic printing papers processed using the stabilizing bath of this invention, the stability of images obtained, and mold prevention of the stabilizing bath are illustrated by the following examples of this invention although the invention shall not be limited to them. In the examples, the test for the stability of the images was determined according to the method described in Photographic Science and Engineering; 11, 5, 295-305 (1967).

Example 1 The compositions of the processing solutions used in above processing steps were as follows:

COLOR DEVELOPER (pH 10.6)

Sodium metaborate g 25.0 Sodium sulfite g 2.0 Hydroxylamine (sulfate) -g 2.0 Potassium bromide g 0.5 6-nitrobenzirnidazole (nitrate) ..g 0.02 Sodium hydroxide ....g 4.0 Benzyl alcohol ml 15.8 Diethylene glycol ml 20.0 N-ethyl-N-fi-(methansulfonamideethyl) p phenylene diamine sulfate g 8.0 a Water to make 1 liter.

STOP-FIXING SOLUTION (pH 4.5)

G. Ammonium thiosulfate 120.0

Sodium metabisulfite 20.0

Glacial acetic acid 10.0

BLEACHING SOLUTION (pH 7.2)

G. Potassium nitrate 25.0 Potassium ferricyanide 20.0 Potassium bromide 8.0 Boric acid 5.0 Borax 2.5 Water to make 1 liter.

HARDENER-FIXING SOLUTION (pH 9.5)

Ammonium thiosulfate g 120.0 Sodium sulfite g 5.0 Boric acid 2 2.5 Formaldehyde (35-40%) ml 40.0 Water to make 1 liter.

Thereafter, the printing paper thus processed was further processed in one of the following compositions A to F (in which Composition A is conventional and Compositions B-F are stabilizing bath compositions of the present invention for 2 minutes at 30.0 C.

Bath

Compound A B C D E F Potassium alum, grams 30.0 30.0 30. 0 Aluminum sulfate, grams 22.0 22.0 Tartaric acid, grams l0. 0

Sodium tartrate, grams Sodium citrate, grams Sodium benzoate, gram Boric acid, grams.. Zinc sulfate, grams 0 Sodium metaborate, grams 20.0

NaOH, grams Water, liter. pH

Bath: Time (min.) A B 3 C 3 D 3 E 3 F 3 As is clear from the above table, the period of time required for finishing the ferrotype drying was shorter in the case of employing the stabilizing baths -B to F of the present invention than was the case in employing conventional stabilizing bath A.

That is, when the ferrotype dryer rotates once over a 3 to 10 minute period, the color print processed by using bath A stuck to the ferrotype plate. As will be expected from the experimental results obtained, the period of time required for drying the color prints can be shortened by using the processing baths B to F of the present invention due to the high drying speed of these compositions. Also, in the case of employing the stabilizing bath of the present invention, a ferrotype dryer having a smaller diameter can be used, making the drying system economical.

Furthermore, the same experiments as described above were repeated using the pre-dryer and the re-wetting means as described in Kodak Products for the Professional 77 (1968/69) and in this case it was confirmed that the drying speed in ferrotype drying was faster in the case of employing the stabilizing baths B to F of the present invention than in the case of employing the conventional stabilizing bath A.

Example 2 According to the procedure of Example 1, color photographic printing papers were subjected to color development, stop-fixing, washing, bleaching, washing, hardener- Bath A B C D E F Time:

3 minutes 0. 2 0. 2 0. 2 0. 2 0. 2 10 minutes 6 0. 1 0. 1 0. 1 0. 1 0. 1

fi'lhe color print could not be separated from the ferrotype 1'0 As is clear from the above results, the samples processed in the conventional stabilizing bath (bath A) had a large amount of electrostatic charges and hence they could not be separated spontaneously from the ferrotype plate or roll or in some cases the samples were scattered away from a receiver caused by the electrostatic repulsion between samples. On the other hand, the aforesaid troubles caused by electrostatic charges were not observed in the case of using the stabilizing bath (baths B to F) of the present invention.

Example 3 According to the procedure as used in Example 1, color photographic printing papers were subjected to color development, stop-fixing, washing, bleaching, washing, hardener-fixing, and washing and thereafter processed in each of the stabilizing baths A to F described in Example 1, followed by ferrotype drying. The samples thus dried were placed under a humidity condition of RH for one day. The samples were then superposed so that the emulsion surfaces thereof were brought into contact with each other and then stored for one day applying a load of l kg./12 8.3 cm. to the stacked samples. The samples processed in the conventional stabilizing bath (bath A) stuck to each other and when they were forcibly separated, the emulsion layers of the samples were stripped to expose the support areas or the supports themselves were sometimes torn. 0n the other hand, no such difficulties occurred in the case of processing in the stabilizing bath of the present invention (baths B to F). The experiment described herein correlates with storing the color prints in an album for a long period of time, particularly under high humidity conditions.

Also, the samples processed in the conventional stabilizing bath became sticky and tended to be contaminated with dust, fingerprints, etc., while no such difiiculties occurred in the case of employing the stabilizing bath of the present invention.

Example 4 According to the procedure as used in Example 1, color photographic printing papers were subjected to color development, stop-fixing, washing, bleaching, washing, hardener-fixing, and washing and thereafter processed in each of the stabilizing baths A to F as described in Example 1, followed by drying. Also, as a control, the same procedure was repeated with the exception that no stabilization process was employed. With these samples, including the control sample, the image stability was measured, the results of which are shown in the following tables.

TABLE 1.-FADE PERCENT OF IMAGE HAVING A DENSITY OF 1.0 AND INCREASED YELLOW STAIN DENSITY (ADy- 1) WHEN THE SAMPLE WAS EXPOSED TO A XENON LAMP OF 110,000 LUX FOR 20 HOURS TABLE 2.FADE PERCENT OF IMAGE HAVING DENSITY OF 1.0 AND INCREASED YELLOW STAIN DENSITY (ADy-2) WHEN THE SAMPLE WAS EXPOSED TO A FLUO- RESCENT LAMP OF 15,000 LUX FOR 10 DAYS I Bath No sta- 5 Stabilizing bath bilizing color image A B C- D bath Yellow, percent 10 10 10 10 10 11 Magenta, percent. 16 15 15 15 15 16 Cyan, pereent 10 10 10 10 10 10 l ADy-2 +0.01 0 0 0 0 0 +0. 07 10 TABLE 3.FADE PERCENT OF IMAGE HAVING DENSITY OF 1.0 AND INCREASED YELLOW STAIN DENSITY (ADy-B) WHEN THE SAMPLE WAS STORED IN THE DARK FOR 14 DAYS AT 37.8" C. AND 90% RH Bath No stabilizing Stabilizing bath color image A B C D E F bath Yellow, percent..- 10 5 5 5 5 5 12 Magenta, percent 5 5 5 5 5 5 6 Cyan, percent" 8 7 7 7 7 8 ADy-S +0. 10 +0.05 +0.05 +0.05 +0. 05 +0. 05 +0. 10

TABLE 4.FADE PERCENT OF IMAGE HAVING DENSITY OF 1.0 AND INCREASED YELLOW STAIN DENSITY (AD -4) WHEN THE SAMPLE WAS STORED IN THE DARK FOR 14 DAYS AT 60 C. AND 70% RH Bath No stabilizing Stabilizing hath color image A B C D E F bath Yellow, percent.-. 2 2 2 2 2 2 2 Magenta, percent. 3 3 3 3 3 3 3 Cyan, percent 10 8 8 8 8 8 l0 AD -4 +0. 08 +0. 05 +0. 05 +0. 05 +0.05 0. 05 +0. 08

TABLE 5.-FADE PERCENT OF IMAGE HAVING DENSITY OF 1.0 AND INCREASED YELLOW STAIN DENSITY (ADy-fi) W HEN THE SAMPLE WAS STORED FOR 7 DAYS AT 707 C. UNDER DRY CONDITION Bath No stabllizing Stabilizing bath color image A B G D E F bath Yellow, percent.-." 0 0 0 0 0 0 0 2 1 1 l 1 1 2 As is clear from the above tables, the light fastness of the samples processed in the stabilizing bath of the present invention (Baths B to F) was almost the same as that of the sample processed in the conventional stabilizing bath (bath 1A) and further in the samples processed in the stabilizing bath of the present invention, the light fastness of the yellow image under a high humidity condition was excellent in comparison with other cases and the formation of yellow stains was less.

Example 5 When the same procedures as used in Example 1 were continued for one Week at C., molds were observed in the conventional stabilizing bath (bath A), whereas no mold was observed in the stabilizing bath of the present invention (baths B to F). Further, only after the stabilizing bath of the present invention was used continuously for one year, was the generation of mold observed.

What is claimed is:

1. A stabilizing bath for a color photographic printing paper consisting essentially of an aqueous composition containing:

(a) a water-soluble aluminum salt,

(b) a polycarboxylic acid or a member selected from the group consisting of an alkali metal and ammonium salt thereof, and

(c) benzoic acid or a salt thereof,

said water-soluble aluminum salt being present in an amount of from 15 to grams per liter, said polycarboxylic acid .or salt thereof being present in an amount of from 2 to 10 grams per liter, and said benzoic acid or salt thereof being present in an amount of from 0.1 to 10 grams per liter, the pH of said stabilizing bath ranging from 2.7 to 4.5-. 2. The stabilizing bath for a color photographic printcarboxylic acid is selected from the group consisting of sodium tartarate and sodium citrate.

5. The stabilizing bath for color photographic printing paper according to claim 1, wherein said bath additionally contains a water-soluble zinc salt in an amount of from 2 to 15 grams per literand additionally contains boric acid or an alkali metal salt thereof in an amount of from 2 to 10 grams per liter.

6. A stabilizing process for color photographic print ing paper which comprises processing said printing paper in an aqueous composition consisting essentially of:

(a) a water-soluble aluminum salt,

(b) a polycarboxylic acid or a member selected from the group consisting of an alkali metal and ammonium salt thereof, and

(c) benzoic acid or a salt thereof,

said water-soluble aluminum salt being present in an amount of from 15 to 40 grams per liter, said polycarboxylic acid or salt thereof being present in an amount of from 2 to 10 grams per liter, and said benzoic acid or salt thereof being present in an amount of from 0.1 to 10 grams per liter,

the pH of said stabilizing bath ranging from 2.7 to 4.5.

7. The stabilizing bath for a color photographic printing paper according to claim 1, wherein said polycarboxylic acid is a member selected from the group consisting of oxalic acid, malonic acid, malic acid, succinic acid, glutaric-acid, adipic acid, lactic acid, crotonic acid, aconic acid, diglycocholic acid, itaconic acid and citraconic acid.

8. The stabilizing bath for a color photographic printing paper according to claim 1, wherein said water-soluble aluminum salt is present in an amount of from 20 to 35 grams per liter, said polycarboxylic acid or salt thereof is present in an amount of from 3 to 7 grams per liter, and said benzoic acid or salt thereof is present in an amount of from 0.2 to 1 gram per liter.

16 9. The stabilizing bath for a color photographic print- References Cited ing paper according to claim 1, wherein said pH ranges UNITED STATES PATENTS from 3.0 to 3.7.

10. The stabilizing bath for a color photographic printg fii ing paper according to claim 5, wherein said water-soluble 5 3525567 8/1970 Levine zinc salt is a member selected from the group consisting 3542553 11/1970 Beach 96 6O of zinc acetate, zinc bromide, zinc chloride, zinc nitrate, and Zinc su1phate OTHER REFERENCES 11. The stabilizing bath for a color photographic print- 10 Glafkides, Photographic Chemistry, vol. 1, 1958, p. ing paper according to claim 1, wherein said Water-soluble zinc salt is resent in an amount of from 5 to 10 rams per men p g I. TRAVIS BROWN, Pr1mary Examiner 12. The stabilizing bath for a color photographic print- M. F. KELLEY, Assistant Examiner ing paper according to claim 1, further containing boric 15 acid or an alkali metal salt thereof in an amount of from 4 to 6 grams per liter. 96-61 22, 50 

